Highest temperature in NYC on August 9?

Platform comparison

Market context

LaGuardia Airport’s high for 9 August is the real reference point here, and the cross-platform picture is unusual because the crowd is effectively pricing a single outcome at certainty while the contract itself is tied to a specific Weather Underground daily-observations reading. Polymarket shows 90–91°F at 100%, with the residual buckets negligible, while the contract wording on rival venues points to the same LaGuardia source and similar temperature banding, leaving little room for a live disagreement unless late observation revisions change the recorded daily high before the cut-off.[4][6]

Historically, August highs in New York City cluster in the upper 80s to low 90s, so a 90–91°F print is a standard warm-season outcome rather than an extreme one. Weather Underground’s latest LaGuardia report on the afternoon of 9 August showed 88.0°F, with a 6-hour high of 89.1°F, and the National Weather Service’s Central Park page was still sitting in the low 80s late in the day, which helps explain why trader consensus had already converged on a sub-92°F finish rather than a more volatile heat-spike scenario.[1][5][7]

What matters now is not the day’s headline forecast but whether the final Weather Underground table for KLGA is amended before the next day’s first datapoint appears, since the market rules state that revisions within the window still count.[4] For cross-platform comparison, the useful check is whether sportsbook-style weather pricing, if available, remains aligned with the same 90–91°F band; absent a late sensor correction or a delayed update, there is no strong sign of a meaningful split between market-implied probability and the broader forecast consensus.[2][3][4]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in NYC on August 9? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to PolyGram, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.